diff --git a/src/github.com/matrix-org/dendrite/clientapi/readers/directory.go b/src/github.com/matrix-org/dendrite/clientapi/readers/directory.go
index 1651fa889..fd5fc778f 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/readers/directory.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/readers/directory.go
@@ -15,7 +15,6 @@
 package readers
 
 import (
-	"fmt"
 	"net/http"
 
 	"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
@@ -39,6 +38,7 @@ func DirectoryRoom(
 	roomAlias string,
 	federation *gomatrixserverlib.FederationClient,
 	cfg *config.Dendrite,
+	queryAPI api.RoomserverQueryAPI,
 ) util.JSONResponse {
 	_, domain, err := gomatrixserverlib.SplitID('#', roomAlias)
 	if err != nil {
@@ -48,11 +48,30 @@ func DirectoryRoom(
 		}
 	}
 
+	var resp gomatrixserverlib.RespDirectory
+
 	if domain == cfg.Matrix.ServerName {
-		// TODO: Implement lookup up local room aliases.
-		panic(fmt.Errorf("Looking up local room aliases is not implemented"))
+		queryReq := api.GetAliasRoomIDRequest{Alias: roomAlias}
+		var queryRes api.GetAliasRoomIDResponse
+		if err = queryAPI.GetAliasRoomID(&queryReq, &queryRes); err != nil {
+			return httputil.LogThenError(req, err)
+		}
+
+		if len(queryRes.RoomID) > 0 {
+			// TODO: List servers that are aware of this room alias
+			resp = gomatrixserverlib.RespDirectory{
+				RoomID:  queryRes.RoomID,
+				Servers: []gomatrixserverlib.ServerName{},
+			}
+		} else {
+			// If the response doesn't contain a non-empty string, return an error
+			return util.JSONResponse{
+				Code: 404,
+				JSON: jsonerror.NotFound("Room alias " + roomAlias + " not found."),
+			}
+		}
 	} else {
-		resp, err := federation.LookupRoomAlias(domain, roomAlias)
+		resp, err = federation.LookupRoomAlias(domain, roomAlias)
 		if err != nil {
 			switch x := err.(type) {
 			case gomatrix.HTTPError:
@@ -67,11 +86,11 @@ func DirectoryRoom(
 			// TODO: Return 504 if the remote server timed out.
 			return httputil.LogThenError(req, err)
 		}
+	}
 
-		return util.JSONResponse{
-			Code: 200,
-			JSON: resp,
-		}
+	return util.JSONResponse{
+		Code: 200,
+		JSON: resp,
 	}
 }
 
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
index 839783c48..217ba4158 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/routing.go
@@ -109,7 +109,7 @@ func Setup(
 	r0mux.Handle("/directory/room/{roomAlias}",
 		common.MakeAuthAPI("directory_room", deviceDB, func(req *http.Request, device *authtypes.Device) util.JSONResponse {
 			vars := mux.Vars(req)
-			return readers.DirectoryRoom(req, device, vars["roomAlias"], federation, &cfg)
+			return readers.DirectoryRoom(req, device, vars["roomAlias"], federation, &cfg, queryAPI)
 		}),
 	).Methods("GET")
 
diff --git a/src/github.com/matrix-org/dendrite/roomserver/api/query.go b/src/github.com/matrix-org/dendrite/roomserver/api/query.go
index dc2acaacf..cae7ec1ae 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/api/query.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/api/query.go
@@ -116,6 +116,18 @@ type SetRoomAliasResponse struct {
 	AliasExists bool `json:"alias_exists"`
 }
 
+// GetAliasRoomIDRequest is a request to GetAliasRoomID
+type GetAliasRoomIDRequest struct {
+	// Alias we want to lookup
+	Alias string `json:"alias"`
+}
+
+// GetAliasRoomIDResponse is a response to GetAliasRoomID
+type GetAliasRoomIDResponse struct {
+	// The room ID the alias refers to
+	RoomID string `json:"room_id"`
+}
+
 // RoomserverQueryAPI is used to query information from the room server.
 type RoomserverQueryAPI interface {
 	// Query the latest events and state for a room from the room server.
@@ -141,6 +153,12 @@ type RoomserverQueryAPI interface {
 		request *SetRoomAliasRequest,
 		response *SetRoomAliasResponse,
 	) error
+
+	// Get the room ID for an alias
+	GetAliasRoomID(
+		request *GetAliasRoomIDRequest,
+		response *GetAliasRoomIDResponse,
+	) error
 }
 
 // RoomserverQueryLatestEventsAndStatePath is the HTTP path for the QueryLatestEventsAndState API.
@@ -155,6 +173,9 @@ const RoomserverQueryEventsByIDPath = "/api/roomserver/queryEventsByID"
 // RoomserverSetRoomAliasPath is the HTTP path for the SetRoomAlias API.
 const RoomserverSetRoomAliasPath = "/api/roomserver/setRoomAlias"
 
+// RoomserverGetAliasRoomIDPath is the HTTP path for the GetAliasRoomID API.
+const RoomserverGetAliasRoomIDPath = "/api/roomserver/getAliasRoomID"
+
 // NewRoomserverQueryAPIHTTP creates a RoomserverQueryAPI implemented by talking to a HTTP POST API.
 // If httpClient is nil then it uses the http.DefaultClient
 func NewRoomserverQueryAPIHTTP(roomserverURL string, httpClient *http.Client) RoomserverQueryAPI {
@@ -205,6 +226,15 @@ func (h *httpRoomserverQueryAPI) SetRoomAlias(
 	return postJSON(h.httpClient, apiURL, request, response)
 }
 
+// GetAliasRoomID implements RoomserverQueryAPI
+func (h *httpRoomserverQueryAPI) GetAliasRoomID(
+	request *GetAliasRoomIDRequest,
+	response *GetAliasRoomIDResponse,
+) error {
+	apiURL := h.roomserverURL + RoomserverGetAliasRoomIDPath
+	return postJSON(h.httpClient, apiURL, request, response)
+}
+
 func postJSON(httpClient *http.Client, apiURL string, request, response interface{}) error {
 	jsonBytes, err := json.Marshal(request)
 	if err != nil {
diff --git a/src/github.com/matrix-org/dendrite/roomserver/query/query.go b/src/github.com/matrix-org/dendrite/roomserver/query/query.go
index 0b72f43aa..a58b586bf 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/query/query.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/query/query.go
@@ -197,6 +197,21 @@ func (r *RoomserverQueryAPI) SetRoomAlias(
 	return nil
 }
 
+// GetAliasRoomID implements api.RoomserverQueryAPI
+func (r *RoomserverQueryAPI) GetAliasRoomID(
+	request *api.GetAliasRoomIDRequest,
+	response *api.GetAliasRoomIDResponse,
+) error {
+	// Lookup the room ID in the database
+	roomID, err := r.DB.GetRoomIDFromAlias(request.Alias)
+	if err != nil {
+		return err
+	}
+
+	response.RoomID = roomID
+	return nil
+}
+
 type roomAliasesContent struct {
 	Aliases []string `json:"aliases"`
 }
@@ -363,4 +378,18 @@ func (r *RoomserverQueryAPI) SetupHTTP(servMux *http.ServeMux) {
 			return util.JSONResponse{Code: 200, JSON: &response}
 		}),
 	)
+	servMux.Handle(
+		api.RoomserverGetAliasRoomIDPath,
+		common.MakeAPI("getAliasRoomID", func(req *http.Request) util.JSONResponse {
+			var request api.GetAliasRoomIDRequest
+			var response api.GetAliasRoomIDResponse
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.ErrorResponse(err)
+			}
+			if err := r.GetAliasRoomID(&request, &response); err != nil {
+				return util.ErrorResponse(err)
+			}
+			return util.JSONResponse{Code: 200, JSON: &response}
+		}),
+	)
 }